Various synthetic roof and wall coverings are known today which are formed of elongated thermoplastic panels that are nailed to a wall or roof support surface in horizontal courses or rows in partially overlapping relation to each other so as to provide a substantially water resistant, protective layer over the support surface. Such panels, which usually are identically molded, commonly are formed with a plurality of rows of simulated building elements, such as shake shingles. Because the panels are identically molded, a panel-to-panel identity can be easily noticed if the panels are not carefully installed and maintained in secure relation to the support surface. Leakage problems between adjoining panels also can occur.
To facilitate installation, such panels commonly are nailed to the wall or support surface along an upper horizontal nailing flange with the lower marginal edge region overlapping a panel in the course immediately below and with one side marginal edge region overlapping the laterally spaced adjacent panel. It is known to interlock the overlapping lower marginal edge region to the upper marginal edge region of the underlying panel in order maintain the panels in secure relation to each other and the support surface upon which they are mounted. It also is know to interlock the overlying side marginal edge regions in order to prevent bowing of the panels in a vertical direction, and preferably, to interlock the overlying side marginal edge regions adjacent each row of simulated building elements.
Heretofore the provision and use of side interlocks in such simulated building panels has created installation problems. Typically the side interlocks require lateral movement of the panel onto a previously installed panel. On the other hand, to lock the upper and lower marginal edge regions, it is necessary to move the panel vertically upwardly relative to the previously installed panel. Hence, engaging of both the upper, lower, and side interlocks has required cumbersome manipulation of the panel. Moreover, when installing the panels along the bottom of framed windows, dormers, or the like, it is not possible to move the panel both upwardly and laterally during installation. Heretofore, the panel often had to be pried or bent in order to engage the various interlocks, which is difficult and time consuming.